Method and means for spinning a banded filament



Feb. 11, 1958 F. LAvAsH 2,822,574 METHOD AND MEANS FOR SPINNING A BANDED FILAMENT Filed April 1'7, 1956 5 Sheets-Sheet 1 Feb. 11, 1958 F LAVASH 2,822,574

METHOD AND MEANS FOR SPINNING A BANDED FILAMENT Filed-April 17, 1956 3, Sheets-Sheet 2 Feb.-11, 1958 E LAVASH 2,822,574

METHOD AND MEANS FOR SPINNING A BANDED FILAMENT Filed April 17, 1956 3 Sheets-Sheet 3 I00 25 g 20 a 1'- Q /"95 24 E a i United States Patefit O METHOD AND MEANS FOR SPINNING A BANDED FILAMENT Francis L. Lavash, New Castle, DeL, assignor to American Viscose Corporation, Philadelphia, Pa., :1 corporation of Delaware Application April 17, 1956, Serial No. 578,825

Claims. (Cl. 18-8) This invention is directed to a process and apparatus for observing the behavior of the spun yarn from the time of its formation until a subsequent point after it leaves the spinning bath. The invention is also directed to a method for the formation of a novelty yarn.

In the spinning of viscose into rayon by conventional methods, the viscose solution is extruded through a spinneret into an acid coagulating bath and the freshly coagulated filament is then treated with various liquids to complete its regeneration, washing, finishing, etc. It is diificult to study the behavior of the filament during its formation in the spinning bath due to the lack of distinguishing characteristics between the viscose filament and the surrounding acid. One cannot determine visually exactly where in the viscose stream coagulation begins, how rapidly it proceeds, and what other chemical phenomena happens during thread development. For some time there has been a need for research and study regarding the actual birth of new yarn as the viscose is extruded into the acid bath in order to determine the physical changes occurring during dehydration, shrinkage, expansion, etc. This knowledge would help immeasurably in the design of tubes for tube spinning, determining the best acid-to-yarn speed ratio, and in many other phases of production for better yarn not presently contemplated. The present invention provides the means for this.

Accordingly the principal object of the present invention is to provide a method and means for observing the behavior of a newly spun yarn at birth. A further object is a means of preparing a banded novelty yarn.

These objects are attained according to the present invention by injecting a colored viscose slug at regular intervals into the main viscose line entering the spinneret, and simultaneously withdrawing from the main line an amount of plain viscose equal to the colored viscose added thereto, whereby a uniform flow of spinning solution is fed from the spinneret into the coagulating bath. The coloring matter serves as a tracer which permits observation of the filament from the time it is formed in the bath up to any point thereafter. The addition of the pigmented solution to the spinning solutions is controlled by a rotary disc valve which is designed to deliver constant increments of colored solution to the spinning solution at regular predetermined intervals, and this is effected Without changing the flow rate of spinning solution through the spinneret and without streaking or blurring of the alternate dyed and undyed sections of the filament. By the introduction of small contrasting bands of color into the new-born filaments at even intervals, any tendency of these bands'to group together in separate areas indicates shrinkage, conversely their separation indicates expansion.

In the drawings,

Figure 1 illustrates diagrammatically the spinning system of the invention.

Figure 2 is a sectional view along cutting plane 2-2 l ce of Figure 1 and illustrates the means for mounting the spinning unit on the spinning bath trough.

Figure 3 is a sectional view of the spinneret.

Figure 4 is a sectional view taken along cutting plane 44 of Figure 3, illustrating the rectangular cross-section of the two side-orifices in the spinneret.

Figure 5 is a side view of the interrupter disc of Figure l, and

Figure 6 illustrates diagrammatically the preferred arrangement of the spinning system, differing from Figure 1 in that the two interrupter discs are employed instead of one.

Referring to Figure 1 a stream of conventional viscose spinning solution in line 1 is mixed with recycled viscose of the same composition from line 2 and the combined streams are pumped by means of pump 5 to a filter and pressure accumulator 6. This vessel contains a candle filter and is of sufiicient capacity to level out the fiuctua tions in the liquidflow and to deliver a uniform stream through exit line 1, mounting bracket 10, and rounder pipe la leading to spinneret 30. A second viscose line 20 connected to a source of pigmented viscose (not shown) is pumped through pump 22 to filter and pressure accumu-' lator 24 which is similar to accumulator 6 already mentioned. This vessel must be able to take considerable pressure, indicated at gage 25, because its flow through interruptor disc 27 is interrupted at regular intervals while pump 22 continues to run steadily. Ordinarily this pressure build up will not exceed 200 to 300 p. s. i., but may go as high as 800 to 900 p. s. i. The colored viscose is ejected at regular intervals through interruptordisc' 27 and then continues its flow through line 20, mounting so dimensioned that it will just accommodate one band' bracket 10, and rounder pipe 20a into spinneret 30. Recycle line 2 extends from spinneret 30 and rounder 2a up through mounting bracket 10 and interrupter disc 27 and terminates with its re-entry into line 1. Mounting bracket 10, illustrated in greater detail in Figure 2, consists of three stationary members 11, 11a, and 11b and three swivelled elements 12, 12a, and 12b connected to rounders 2a, 1a, and 20a respectively. Elements 12, 12a, and 12b are mounted on a common swivel so as to permit the spinneret 30 to be swung into and out of the spinning bath trough 16. A draw bolt 14 pulls elements 11, 11a, and 11b together as one element. The assembly is secured to the edge of trough 1b by suitable clamping means 15 (Figure l).

Spinneret 30 as seen in Figure 3 comprises a jet coupling made up of supply head 31, jet 33, a gasket 34 forming a seal between the flange of jet 33 and. supply head 31, and a coupling 37 securing jet 33 to supply head 31. Supply head 31 has a central bore 1b connecting with the main rounder pipe 1a, and two connecting bores 20b and 2b which connect to colored viscose line 20a and return line 2a, respectively. Side bores 20b and 2b open into the main bore 1b through orifices 20c and 2c, respectively, which are of rectangular cross-section as shown in Figure 4. At regular intervals, as determined by interrupter disc 27 and other factors, a shot of pigmented viscose is injected via line 20, rounder 20a, and bore 20b through rectangular orifice 20c into central; bore 1a.,

Since the long dimension of orifice 20c is equal to the diameter of main bore 1a as shown in Figure 4, this shot is sufficient to just fill the cross-section of bore 1a with a band of colored viscose, the exact thickness of the band being determined by the width of orifice 20c. Simultaneously, to prevent slubbing, an equal amount of viscose is displaced from line 16 through orifice 2c,,bore 2b, etc., returning through disc 27 to main line 1.

A dish-shaped recess 39 separates the inner face of jet 33' from the muzzle of supply head 31. Recess 39 is of viscose, whether plain or colored, thus preventing in- -Patented'Feb. 11, 1958- termixing of the colored and uncolored bands. Obviously ifrecess39 were too small to accommodate a band of viscose, said band would back up into bore 1a, forming a streamer in the succeeding'band and thus blurring the sharp" color lihes desired. If, on the other hand, recess 39 were too large tobe filled with oneband the following band would partially enter it, causing intermixing and streamer" formationwithin recess 39. Viscose ejected through jet 33 is carried through spinning tube 40 concurrently withtheacid spinning bath. Coagulation takes place in tube 40 and a striped or banded yarn 42 emerges therefrom.

Interrupter disc 27 as shown in Figure consists of a housing formed of two plates 59 and 51, plate 56 being recessedat 52 and 53 to provide suificient clearance for the rotation of disc 55. Disc 55 is mounted on shaft 57 which inturh is'driven by gear 60, the latter being affixed to shaft 57 by means including nut 61. Shaft 57 is enclosed in sleeve 62' and bearing 63 and is keyed at 65 to hub 66, which is secured to disc 55 by screws 67. The valve portion for line comprises a threaded bolt fitting 70'in plate 51 and a matching bolt fitting 70' in plate 50. Takingbolt 70 as representative, this element is threaded at its periphery 72 to fit into the matching bore of plate 51, and equipped externally with a heXago-' nal or other suitable lock nut 74 and adjustable bushing housing 75 to receive the end of pipe 20. Internally bolt fitting 70 comprises a bushing 77 having a slick durable surface such as Teflon fitted against a seat 78,

and a bore 79 connecting with passage 81 in disc 55. Bushin'g'77 isadjustable relative to plate 55 to permit a minimum of leakage of viscose during its passage from passage 79 to passage 81. Bolt fitting 76' is a duplicate of fitting 70 already described and is provided with a similar bushing 77' to prevent leakage of viscose from passage-J81 to passage 79'. Both bushings 77, 77 are adjusted' relative to the outer faces of disc 55 by adjustable bushing housings 75, 75 and are held in position by lock nuts 74, 74. 'A similar arrangement is shown for line 2 which communicates with passage 81' in disc 55 by means of fittings 80, 80' which duplicate fittings 70,- 70 just described.

It is evident that viscose can fiow through interrupter valve 27 only when the bores in plates 50, 51 are in alignment with the bores in spinning disc 55. The frequen'cy with whichthese passages register to permit viscose fiow depends on the number of passages such as 81, 8-1 whichare spaced peripherally around the annulus of disc-55, as well as on the speed of rotation of the disc 55.

In a specific embodiment a conventional viscose containing 68% cellulose, 4-8% NaOH, and from -100% CS based on cellulose was pumped through line 1 by pump 5. Pump 5 was a 2.99 cc. pump operating at 70 R. P. M. so as to deliver 203 cc./min. (227.9 gms./min.). Pigmented viscose of the same composition but colored with carbon black was delivered through pump 22, a 2.9 cc. pump operating at 26 R. P. M. so as todeliver 75.5 cc. or 79 gms./min.

Interrupter disc 27 was run at a speed of 154 R. P. M. andcontained 30'-holes-'% inch in diameter on a 3 inch circle. On this basis the disc made one revolution in .389 second, the time between holes was .013 second, and the time of passage through one of the holes was .0039 second.

'Using these rates, plain viscose' was supplied to the spinneret at a speed of 28.2 meters/min. and the pigmented viscose wasinjected into it through line 20 at the rate of 4440 impregnationslmim, the volume of each impregnation being .0159 cc. The pressure behind the plain viscose was approximately 125p. s. i. Jet 33 contained 720 holes and it spun filaments having dyed bands 3 4 inch wide at inch intervals, in other words, alternate black and white bands inch wide.

The pressure with which thepigmented viscose is injected into main bore 1b is independent of the pressure of the plain viscose in line 1b so long as an equal volume of viscose is displaced through return line 2 at the same pressure. Hence in the example just given the viscose returned through line 2 to interrupter disc 27 will pass therethrough at the same rate and under the same pres sure as the colored viscose is admitted therethrough from line 20 in the other direction. If the return line 2 bypassed disc 27 and fed directly back into line i the system would be inoperative because all the viscose in the spinneret would run back through line 2 instead of passing through the restrictive holes in the jet 33.

Figure 6 illustrates the preferred arrangement of the spinning system. Since most of the elements of Figure 6 duplicate those of Figure 1 the same numbers are used in both drawings to designate those elements common to both. The system of Figure 6, however, difiers from that of Figure 1 in that instead of having a single interrupter disc 27 to meter viscose through lines 2 and 20 it employs a pair of interrupter discs 9Q, tea in lines 2 and-2'4} respectively. Both are driven from a common gear through pinions 91 and 92 which in turn are mounted on shafts 4 and 95 respectively, so as to rotate associated discs 100, 99 at the same speed. Discs 99 and 100 are duplicates as to size and design and diiier from the arrangement of Figure 5 only in that they require but one set of conduit fittings, not two. Thus, disc 109 which meters colored viscose through line 20 employs the same combination of fittings 70, 70' illustrated in the upper half of Figure 5 but does not of course employ the fittings 80, 30 shown in the lower half of Figure 5. Conversely, disc 99 which returns plain viscose through line 2 employs the fittings 80, 30 illustrated in the lower half of Figure 5 but not the fittings 7t), 70' shown in the upper half of the figure. Except for the double disc arrangement just described the flow pattern through the remainder of the apparatus of Figure 6 duplicates that in Figure 1 and hence need not be described again.

The advantage of the arrangement of Figure 6 over that of Figure 1 is that it avoids the use of the same disc passages for both plain and colored viscose. The latter arrangement can lead to some contamination of the two streams; e. g., a trace of colored viscose may remain. in passage 81 (Figure 5) after ejection of colored viscose therethrough, so that when this passage has rotated to the position of passage 81' it will stain the plain viscose returning at that point through line 2. In the same way the uniformity of the colored viscose can be marred by traces-of plain viscose. The use of a separate disc for each stream eliminates any problem of intermixing.

The two discs 99, 100 are timed so that when disc 100 is; introducing a pigmented viscose slug, disc 99 is recycling an equivalent sizedslug of plain viscose through line 2. This in turn equalizes the pressure and volume in lines 20, 20a, etc., andin lines 2, 2a, etc., which maintains a constant unvarying pressure through the jet 33 to form a constant cross-section yarn.

Suitable colored inorganic pigment may be employed to-obtain the desired color or shade. For a yellow color, ochre, sienna, chrome yellow, tin bronze, etc., may be employed. For a red color, Venetial red, red lead, vermillion, etc., may be-employed. For a blue color, ultramarin e, Prussian blue, Milori blue, etc., may be used. For-green, .Guignets green, verdigris, chrome green may be employed. For brown, raw umber, burnt umber or Vandykebrown maybe used. To obtain metallic effects, finely divided or colloidal metals may be employed. For shading, thatfis to g'etdarker colors, lamp black, graphite or other black pigment may be added. To obtain any other colors, the pigments may be mixed as is well understood in the paint art.

The pigment is preferably added to the dope or spinning solution containing the cellulose compound in the form of a concentrated suspension in a liquid. The amount of pigment added will vary with a degree of subdued luster and the depth of color desired and the nature of the pigment employed and will generally be from 0.1 to 10% of the weight of the cellulosic material present in the finished yarn. The pigment is preferably in very fine form, the particles having a diameter of less than 0.1 to microns for increased covering power. It is of importance to have the pigment of very fine size in order to obtain the desired depth of color without the necessity of incorporating such a large amount of pigment as to deleteriously affect the strength and the other properties of the yarn. This fine size may be obtained by grinding the inorganic colored pigment either with water, an oil, part of the spinning solution, or the solvent used in the spinning solution in a ball mill or colloid mill.

The viscose used may have any spinnable composition and may be a normal or plain viscose having a sodium chloride salt test value of from 3 to 6, containing from 6 to 9% cellulose, from 6 to 9% sodium hydroxide and of normal spinning viscosity, i. e., having a ball fall viscosity of 35 seconds at 18 C.

The setting bath into which the modified viscose is extruded may be a coagulating and cellulose-regenerating bath of the composition normally used in the manufacture of fibers .or yarns from viscose. Aqueous baths containing from 7 to 13.5% sulfuric acid and from 18 to 28% sodium sulfate are satisfactory. The bath may also contain comparatively small amounts, for example, from 0.1 to 5% of zinc sulfate, as well as small amounts of other adjuvants or assistants. If it is desired to produce self-crimpable fibers of the type described in U. S. 2,517,694 to Merion and Sisson, spinning baths as described in that patent may be used.

The invention is also adapted to the production of banded filaments by the two-bath process in which the modified viscose is extruded into a coagulating bath which effects little, if any, regeneration of the cellulose, and the article comprising cellulose xanthate is subse quently treated with a cellulose-regenerating medium.

The banded filament formed by the process of this invention is easily followed by the eye, permitting one to observe, for example, the degree of tension or relaxation of the yarn in the spinning tube, so as to adjust the drawoif speed accordingly. The novelty yarn itself finds utility in textiles.

The foregoing description, along with the drawings, should be considered illustrative of the invention, not limiting in itself. For example, it would be possible to form a filament having a plurality of differently colored bands without departing from the spirit of the invention.

This could be effected by providing a series of pigmented viscose injection lines instead of only one, each line introducing a differently colored viscose and each equipped with its own interrupter disc, pump means, etc., and each injection point being offset by a cooperating withdrawal orifice for the displaced plain viscose.

I claim:

1. Method of forming artificial filaments comprising injecting an additive spinning solution of one color into a stream of primary spinning solution of another color just prior to extrusion through the spinning jet into the spinning bath, whereby a disc-shaped segment of the primary spinning solution is displaced from the stream and replaced by a disc-shaped segment of the additive solution, simul taneously drawing off the displaced segment so as to maintain a uniform flow of spinning solution through the jet regardless of the additions of additive spinning solution, and withdrawing from the spinning bath continuous filaments having bands of contrasting color, the displaced segments being withdrawn under a pressure sufficient to prevent pressure loss at the spinneret.

2. Process of claim 1 wherein the primary spinning solution is a viscose solution and the additive solution is a viscose of substantially the same composition but with a colored component added thereto.

3. Process of claim 2 wherein the spinning bath is an acidic coagulating bath.

4. A process of forming regenerated cellulose filaments having alternating bands of color comprising continuously passing a stream of viscose through a conduit into a spinning jet, continuously extruding this stream through the jet into a coagulating bath to form a filament therein, periodically injecting pigmented viscose into said stream just prior to extrusion through said jet, thereby displacing .a band of viscose from said stream and replacing it with a band of pigmented viscose, and simultaneously drawing off the displaced band of viscose under a pressure suificient to prevent pressure loss at the jet so as to maintain a uniform flow of viscose through the jet, whereby a filament of regular cross-section but having pigmented bands at regular intervals is formed within the coagulating bath.

5. Process of claim 4 comprising recycling the viscose displaced from the main stream by the injection of colored viscose.

6. Process of claim 4 comprising injecting the pigmented viscose into the other viscose at the same pressure as that which must be overcome by the displaced viscose, said pressure being in excess of that at the jet, so that the main stream of viscose will discharge through the 'et.

7 Apparatus for producing regenerated cellulose filaments of uniform cross-section but having bands of contrasting colors at selected intervals along its length comprising a spinneret, a central conduit connected to said spinneret, means for supplying a continuous stream of plain viscose to said central conduit for extrusion through said spinneret, auxiliary means for adding increments of colored viscose to said central conduit, a return conduit for withdrawing a side stream of plain viscose from said central conduit at a point upstream from the point of colored viscose injection and in an amount equal to that added through said auxiliary means, a restriction in said conduit which offers at least as great a resistance to viscose flow as does the spinneret, whereby bands of colored viscose may be injected into the plain viscose stream at regular intervals and equivalent amounts of plain viscose withdrawn simultaneously therewith through said return conduit, thereby maintaining an unvarying flow rate through the spinneret.

8. Apparatus of claim 7 wherein the means for adding colored viscose to, and for returning plain viscose from the central conduit includes a control valve coordinating the addition of colored viscose to the central conduit with the withdrawal of plain viscose through the return conduit, whereby both operations are effected simultaneously and without disrupting the continuous flow of viscose through the spinneret.

9. Apparatus of claim 8 wherein said valve comprises a rotatable apertured disc and passages extending from opposite faces of the disc to the inlet and outlet ports respectively of the valve, the apertures in the disc extending through the disc between the opposite faces thereof, and means for rotating the disc to align the apertures with the passages in succession.

10. Apparatus as defined in claim 9 in which a pump and a conduit connecting the pump to the inlet port of the valve are provided to supply the secondary quantity of filament-forming material.

11. Apparatus for producing artificial filaments of uniform cross-section but having bands of contrasting color along their length comprising a spinneret having a multiple-orifice jet, a central conduit leading into said jet through the axis of said spinneret, a second conduit opening into said central conduit at right angles thereto, a third conduit opening out of said conduit at right angles thereto and upstream from the opening of said second conduit, both of said second and third conduits opening into said central conduit through orifices of substantially the same shape and size so that when a slug of liquid is injected, through the second conduit a slugof equal size is Withdrawn from the central conduit through the third conduit,:means for supplying a continuous stream of plain viscose to said central conduit, means including an interrupterva-lve in said second conduit to permit intermittent flow of colored viscose therethrough with a resulting intermittent injection of colored viscose into the plain viscose stream, means including a second control valve in said third conduit, said valves being similar in design and capacity and so synchronized that both interrupt the flow of liquid therethrough simultaneously and both permit flow of liquid therethrough simultaneously, whereby the injection of colored viscose into the central conduit simultaneously displaces an equal volume of plain viscose into the third conduit without changing the flow rate to the jet or the spinneret pressure at the jet.

12. Apparatus of claim ll wherein the orifices opening into the central conduit from the second and third conduit s are of the same dimensions and shape, each orifice being of rectangular cross-section with one side at right angles to the main axis of the central conduit and equal in length to the diameter of the central conduit, so that when a slug of colored viscose is injected through the second conduit it forms a colored band occupying the entire cross-section of the central conduit, thereby preventing the intermixing of plain and colored viscose within the band.

13. Apparatus of claim 11 wherein a dish-shaped recess separates the inner face of the jet from the discharge end of the central conduit, said recess being so dimensioned as to just contain one band of colored viscose, whereby said band is extruded as a complete unit without being marred by the intermixture of plain viscose therewith in the jet.

14. Apparatus for producing artificial filaments of uniform cross-section but having bands of contrasting color along their length comprising a spinneret having a multipie-orifice jet, a central conduit leading into said jet through theaxis of said spinneret, a second conduit opening into said central conduit at right angles thereto, a third conduit openingouttof said conduit at right angles thereto and upstream from the opening of said second conduit, both .of said second and third conduits opening into said central conduits through orifices of substantially the same shape and size so that when a slug of liquid is injected into the central conduit a slug of equal size is withdrawn upstream from the central conduit through the third conduit, means for supplying a continuous stream of plain viscose to said centralconduit, means for supplying intermittent injections of colored viscose through said second conduit into the central conduit, separate interrupter valves in said second and third conduits, said valve permitting the injection of a slug of colored viscose through the second conduit simultaneously with the withdrawal of an equal sized slug of plain viscose through the third conduit, whereby the pressure across the orifices of the two conduits at the central conduit is maintained constant, thereby maintaining a constant flow rate through the spinneret.

15. Apparatus of claim 14 wherein the interrupter valve is a rotary disc valve comprising inlet ports on one side of the valve, discharge ports on the opposite side of the valve, a rotatable apertured disc between the two sets of ports, the apertures in the rotatable disc registering at regular intervals with both an inlet port and an outlet port so as to align them temporarily and permit a stream of spinning solution to pass through the valve.

References Cited in the file of this patent UNITED STATES PATENTS 

7. APPARATUS FOR PRODUCING REGENERATED CELLULOSE FILAMENTS OF UNIFORM CROSS-SECTION BUT HAVING BANDS OF CONTRASTING COLORS AT SELECTED INTERVALS ALONG ITS LENGTH COMPRISING A SPINNERET, A CENTRAL CONDUIT CONNECTED TO SAID SPINNERET, MEANS FOR SUPPLYING A CONTINUOUS STREAM OF PLAIN VISCOSE TO SAID CENTRAL CONDUIT FOR EXTRUSION THROUGH SAID SPINNERET, AUCILIARY MEANS FOR ADDING INCREMENTS OF COLORED VISCOSE TO SAID CENTRAL CONDUIT, A RETURN CONDUIT FOR WITHDRAWING A SIDE STREAM OF PLAIN VISCOSE FROM SAID CENTRAL CONDUIT AT A POINT UPSTREAM FROM THE POINT OF COLORED VISCOSE INJECTION AND IN AN AMOUNT EQUAL TO THAT ADDED THROUGH SAID AUXILIARY MEANS, A RESTRICTION IN SAID 